
// https://leetcode.cn/problems/path-with-maximum-gold/description/

class Solution
{
    int res = 0;
    int m;
    int n;
    int dx[4] = { 0, 0, 1, -1 };
    int dy[4] = { 1, -1, 0, 0 };

public:
    int getMaximumGold(vector<vector<int>>& grid)
    {
        m = grid.size();
        n = grid[0].size();
        for (int i = 0; i < m; ++i)
        {
            for (int j = 0; j < n; ++j)
            {
                if (grid[i][j] != 0)
                    dfs(grid, i, j, grid[i][j]);
            }
        }
        return res;
    }

    void dfs(vector<vector<int>>& grid, int i, int j, int sum)
    {
        res = max(res, sum);
        int num = grid[i][j];
        grid[i][j] = 0;

        for (int k = 0; k < 4; ++k)
        {
            int x = i + dx[k];
            int y = j + dy[k];
            if (x >= 0 && x < m && y >= 0 && y < n && grid[x][y] != 0)
                dfs(grid, x, y, sum + grid[x][y]);
        }

        grid[i][j] = num;
    }
};